The fusible link circuit breaker was developed in the early eighties to obtain wire separation relief on vehicle electronics systems. The original intent was to prevent propagation of wire damage to adjacent wires if a circuit breaker was to malfunction in a closed position and fail to open on a fault. A failure mode in older circuit breakers with silver cadmium or silver tungsten contacts was to weld together or be jammed from opening on a heavy fault current. Additionally, in a solid state power controller (SSPC), these failsafe fuses can only serve one thermal rating that causes wire integration issues by limiting the choice as to which connector or pin a load wire will come from.
In order to gain the most wire weight savings from the application of Solid State Power Controller (SSPC) technology, a new approach to failsafe design must be devised that does not depend on a physical fusing device. Current solutions use fuses as failsafe protection for a shorted Field Effect Transistor (FET) condition. Some SSPCs do not have backup protection (the Secondary Power Distribution Assembly (SPDA) on the MMA (Multi Mission Airplane)). There exists a need to allow a circuit to keep functioning even though there may be a shorted FET, where a Built-In-Tester (BIT) will report the shorted FET failure to a maintenance computer upon the next power up. It is with respect to these and other considerations that the disclosure herein is presented.